Lithographic step and repeat system



June 1955 H. c. KESSLER, JR 2,711,031

LITHOGRAPHIC STEP AND REPEAT SYSTEM Filed May 6, 1952 3 Sheets-Sheet l .D ID

V INVENTOR. HARRY C. KESSLER, J'r.

BY 7 fi d a4 ATTORNEYS June 21, 1955 H. c. KESSLER. JR 2,711,031

LITHOGRAPHIC STEP AND REPEAT SYSTEM I Filed May 6, 1952 :s Sheefs-Sheet 2 INVENTOR.

HARRY C, KE SSLER, J'r. BY

ATTORNEYS June 21, 1955 H. c. KESSLER, JR 2,711,031

' LITHOGRAPHIC STEP AND REPEAT SYSTEM Filed May 6, 1952 5 Sheets-Sheet 3 INVENTOR.

HARRY G. KESSLER, J'r.

ATTORNEYS,

LITHOGRAPHIC STEP AND REPEAT SYSTEM Harry C. Kessler, .lia, Philadelphia, Pa. Application May 6, 1952, Serial No. 236,379 9 Claims. (Cl. 33-4345) in the lithographing art the making of a series of prints upon a sensitized press plate or film from a single negative or positive is known as step and repeat. Step and repeat is also used in making multiple positives on film from a single negative, or conversely to make multiple negatives from a single positive. The commonest use of step and repeat is to register work that is in two or more colors.

The process requires precise localization of the positive or negative upon the impression-receiving film surface or press plate so as to secure exact registry of every impressed print with preceding and following adjacent impressed prints or with previously impressed prints. This presents difiiculties, especially where a plurality of different colors must register with one another.

The main object of the invention is to achieve the above stated purpose with a minimum of visual judgment but by means of maximum simplicity involving merely mutually engageable means between the bed carrying the film or press plate and an element movable step by step on the bed, and mutually engageable means between said element and a unit, movable step by step on such element, to which the positive or negative is attached. These mutually engageable means positively and accurately enable, and in fact necessarily effect, a succession of predetermined exact positionings of the positive or negative relative to the film with no exercise of skill on the part of the operator, who merely shifts the movable parts into successive positions, the exact positioning specified being effected by the relative location of the mutually engaging means. v

Such operation is, of course, dependent upon precisely locating the mutually engaging means above specified on the specified devices utilized in the step-by-step operation. To this end I have provided a construction whereby the bed and the element movable step-by-step thereon may be equipped with dowels or some equivalent thereon spaced apart to precise distances and otherwise arranged as to insure that the succession of movements of the movable parts in the step-by-step operation will elfect the exact registrations specified.

In the drawings, which show a preferred embodiment of the invention:

Fig. l is a plan view of the construction utilized in the step-by-step operation.

Fig. 2 is a plan view of a dowel locator board and mechanism carried thereby which is operable to secure the dowels in required positions to the bed and the element movable step-by-step thereon shown in Fig. 1.

Fig. 3 is an end view of the bar on which the dowel locator is slidable.

Fig. 4 is a perspective view of the dowel locator.

Fig. 5 is a detail view of a part of the record strip, one of the dowels being bent up to show the adhesive by means of which it is attached.

Fig. 6 is a detail view of the backer.

Referring first to Fig. l:

The sensitized press plate or film a is placed upon a ice sheet of vinyl plastic b, which is hereinafter called the bed. The bed b is of greater dimension, measuring from head to foot, than the film or plate, it being understood that that part of the bed at the bottom of Fig. 1 is referred to herein as the head and that part at the top of Fig. 1 is referred to as the foot.

Along the head and foot respectively of the bed 11 are narrow plastic strips 0 and c secured to the bed.

Plastic discs d, called dowels, coated on one side witha pressure sensitive adhesive, are applied to the strips 0 and c. The dowels carried by each strip are directly opposite the dowels applied to the other strip, and the dowels carried by each strip are spaced one from another a distance corresponding to the width of the design to be printed.

Applied to the bed b is a carrier e, which is a sheet of clear or matte vinyl plastic of a length to reach from head to foot of the bed. Projecting from the center of the ends of the carrier e are ears having holes, there being a round hole e at one end (say the head end) and an elongated hole, or slot, e at the other end. These holes fit the plastic dowels d placed upon the head and foot strips, c and c, of the bed.

Applied to the carrier e is a backer 1, so called because it is placed back of the negatives or positives. The backer is of clear vinyl plastic. Near one edge the backer has a round hole f and near the opposite edge an elongated hole f These holes are opposite one another and in the embodiment herein shown and described are midway between the other two opposite edges of the backer and engage dowels s placed upon the carrier e along the opposite edges thereof thatextend from head strip to foot strip. The dowels s along one side of said edges are directly opposite the dowels along the opposite edge, and the dowels along each edge are spaced apart distances corresponding to the length of the step required by the job-,3

In line with the centers of the holes f (non-photographic) fine line g, and perpendicular thereto and aligning with the center of the backer is another blue (non-photographic) fine line g. These are positioning lines for matching the negative or positive with the blue lines of the backer 7. The negative or positive is then secured to the backer with Scotch tape or similar pressure sensitive adhesive tape.

It will be understood that all that is required in the specific embodiment of the invention that has been selected for illustration are the two non-photographic lines g and g. It should be understood, however, that in addition to the central fine line g a number of uniformly spaced apart parallel non-photographic lines g may be provided as shown in Fig. 6, the only requirement for operativeness being that the holes f and f shall be so located and f is a blue that their centers will be intersected by one of such lines.

Preferably, also, but not necessarily, formly spaced apart lines g may be provided, such lines a multitude of rectangles.

The operation of step and repeat comprises moving the backer f, with negative or positive attached, to predetermined positions on the carrier 2 and of moving the carrier to predetermined positions on the bed b.

Given the above described arrangement of dowels d on the head and foot strips of the bed b, of holes at the ends of the carrier e engageable with said dowels, of dowels on the carrier e and of holes in the backer f engageable with the last named dowels, it is clear that each backer may be located at its precise desired and required position without the necessity of the operators being dependent upon, or even being guided by, visual judgment.

However, to eifect the hereinbefore described operation, which can be understood by reference to Fig. l

a number of uniforming with lines g and g parallel to the center line g I alone, requires accurate positioning of the described dowels and holes. To effect this, reference is made to the remaining figures and particularly to Fig. 2, in which it 'is a dowel locator board. Extending lengthwise, and approximately centrally, of the board is a steel bar i having, in end view and in cross-section, somewhat the shape of a keyhole, as shown in Fig. 3. Slidable along this bar is a dowel locator k, shown in detail in Fig. 4, which consists of two metal parts that are swingable independently on the bar i like the two parts of a door hinge. Attached to these two parts respectively of lo cato'r k are small plastic sheets or strips in and 11 extending'at'right angles to the bar i and in alignment with each other. Engraved on each strip are longitudinally extendin'g center lines, the center line of each strip being in alignment with the center line of the other strip. In plasticshee't m are formedtwo'holes and in plastic sheet n four holes; all the holes being centered on the engraved lines. An explanation of the distances of these holes from the center of the bar i is given hereinbelow.

On one side of the bar i and parallel thereto is a steel rule 0, which is graduated in any suitable selected way. As shown, and for convenience, the rule has one edge, say that more distant from the bar i, engraved with the zero mark in the middle and thence to right and to'leit, while along the opposite edge, or that nearestthe bar 1', the graduations are conventional, starting from the left hand' end of the rule.

On the side of the bar i opposite to that at which the steel rule 0 is located, and at about the same distance from the rule, are three metal pins p, which hold in position a strip p, called the record strip, of vinyl plastic punched to fit the pins.

By referring back to Fig. 1 it will be observed that the bed 12 is provided with holes b at its four corners. The bed I) is now placed on the locator board h with its head strip 0 close to the rule 0, the holes b along that edge of the bed being fitted upon two pins r, r so placed on the locator board it that the inside edge of the head strip of the bed b is held parallel to the bar i and rule 0 and with the center point of the head strip opposite the middle of the rule 0.

Through a dowel hole in the plastic sheet In of the dowel locator k the plastic dowels d can be placed upon the head strip of the bed [7. To place these dowels in position according to the layout of the job, the dowel locator is moved along the bar 1' to the necessary positions along the rule 0. When a dowel d is placed on the head strip of the bed b another dowel s is placed on the record strip p through a dowel hole located for this purpose in theplastic strip 11 on the other side of the bar 1'. By sliding the dowel locator k along the bar 1', so that the engraved center line on the strip in aligns with equally spaced-apart graduations on the rule 0, all necessary dowels, equally spaced apart, may be placed on the head strip of the bed 12 and on the record strip p.

After all necessary dowels have been placed on the head strip of the bed b and the record strip p, the bed is removed from the board It and moved into such position that the holes b at opposite ends of the foot strip of the bed b are engaged with the pins r' on the board on the opposite side of the bar i. The locator k is now shifted into such position that through a hole in the plastic sheet 11 of the locator, dowels are placed on the foot strip of the bed to match dowels previously placed on the record strip; that is, the locator is moved step by step from one dowel of the record strip to the next, and dowels applied.

The procedure for placing dowelss on the carrier e is similar to the above described procedure for placing dowels d on the head and foot strips of the bed.

The bed b is removed. from the dowel locator board h and the carrier e is positioned on the board parallel to the bar 1 and rule 0 in the position theretofore occupied by the bed b, as shown in Fig. 2. This is done by fitting the holes e and e on the two pins t. Through a dowel hole in the plastic sheet in of the dowel locator k dowels s can be placed along one side of carrier e in accordance with the layout of the job. When a dowel s is placed on the carrier e another dowel is placed on the record strip 2 through a dowel hole located for this purpose in the the next and dowels s applied to the carrier e through a.

hole in the plastic sheet 12 of the dowel locator it.

Where in the claims 1 specify a negative it will be F understood that a positive is an equivalent thereof.

What is claimed is:

l. The hereindescribed structure for making a series-of prints upon a sensitized press plate or film from a single negative or positive, for making multiple positives or negatives from a single negative or positive, and for registering work that is in a plurality of colors, all by the known step and repeat process, which comprises a bed, dowels thereon arranged along the head and foot of the bed, a carrier and means at the ends thereof removably engageable with the dowels on the head and foot of the bed, dowels arranged lengthwise on the carrier, a transparent backer adapted to have a negative attached thereto, said backer having one or more non-photographic lines extending transversely of the carrier when the backer is applied thereto, the backer having oppositely disposed holes with the centers of which a non-photographic line intersects, said holes being removably engageable with the dowels on the carrier.

2. The structure defined in claim 1 in which the dowels on the head and foot of the bed are equally spaced apart at distances corresponding to the width of the design to be printed from the negative attached to the backer, the dowels on the carrier being spaced apart at distances corresponding to the length of the negative.

3. A structure adapted for use in positioning the dowels on a bed employed in the step and repeat operation as herein described, which comprises a dowel locator board, a bar extending across the board, a graduated rule extending lengthwise of and parallel to the bar, means by which the bed may be applied to the board with the edge thereof to which the dowels are to be applied extending lengthwise of and parallel to the rule, a record strip applied to the board and extending lengthwise of and parallel to the bar and on the side thereof opposite to that at which the rule is located, a dowel locator movable step by step along the bar, a strip carried by the dowel locator and extending at a right angle to the bar in operative relation with the rule, a second strip carried by the dowel'locator and extending at right angles to 3 the bar and in operative relation with the record strip,

each of said strips having a hole through which, as the dowel locator is moved step by step along the bar, dowels may be applied to the bed and record strip respectively.

4. The structure defined in claim 3 in which the holes in the strips are located centrally between their opposite longitudinal edges and in which each strip has a longitudinally extending guide line, located centrally between its opposite longitudinal edges, adapted to be.

aligned, in the step by step movement of the dowel lo-. cator, with predetermined graduations on the rule.

5. The structure defined in claim 3 comprising also means for applying a carrier to the board, the second strip having a hole through which, as the dowel locator is moved step by step along the bar, dowels maybe applied to the. carrier.

6. The hereindescribed structure for making a series of prints upon a sensitized press plate or film from a single negative or positive, for making multiple positives or negatives from a single negative or positive, and for registering work that is in a plurality of colors, all by the known step and repea process, which comprises a bed, dowels thereon arranged along the head and foot of the bed, a carrier and means at the ends thereof removably engageable with the dowels on the head and foot of the bed, dowels arranged lengthwise of the carrier, a transparent backer adapted to have a negative attached thereto, said backer having one or more nonphotographic lines extending transversely of the carrier when the backer is applied thereto, the backer having oppositely disposed holes, said holes being removably engageable with the dowels on the carrier.

7. The process of producing a bed and record strip equipped with dowels so arranged as to simplify the step and repeat operation as herein described, which comprises moving a member equipped with a hole along one edge of the bed in a direction parallel to said edge and in a succession of steps covering equal distances and simultaneously moving another hole in said member in said succession of steps along the record strip in a direction parallel to the longitudinal extension of said strip and at each step inserting dowels in said holes and applying them respectively to the bed and to the record strip.

8. The process of producing a bed and record strip equipped with dowels so arranged as to simplify the step and repeat operation as herein described, which comprises positioning said bed with one edge adjacent to one side of a movable member and under a hole therein, positioning said record strip to extend parallel to said edge and under a second hole in said movable member, moving said movable member over said bed and said record strip in a succession of steps and at each step inserting dowels in said holes and applying them respectively to said bed and said record strip, thereafter positioning said bed with the opposite edge thereof under a third hole in the opposite side of said movable member and moving said movable member over said bed in a succession of steps as determined by the positions of said dowels applied to said record strip and at each step inserting a dowel in said third hole and applying it to said bed.

9. Apparatus for use in positioning dowels on a bed employed in the step and repeat operation as herein described, which comprises a dowel locator board, a slide member, a guide for said slide member extending across said board, means providing graduations extending lengthwise of said guide and adjacent to said slide member, said slide member having extensions on opposite sides of said guide with at least one hole in each of said extensions, means for locating a bed on said board in definite positions on both sides of said slide with edges of the bed located beneath said extensions and the holes therein, and means for locating a record strip on said board in definite position extending lengthwise of said guide and beneath one of said extensions, the last mentioned extension being provided with a hole positioned above said record strip in various positions of the slide member.

References Cited in the file of this patent UNITED STATES PATENTS 365,938 Phillips July 5, 1887 1,975,181 Springstead Oct. 2, 1934 2,011,584 Lengel et al. Aug. 20, 1935 2,099,364 Hunter Nov. 16, 1937 2,387,986 Evans Oct. 30, 1945 2,399,610 West et al. Apr. 30, 1946 2,465,227 Heatley Mar. 22, 1949 2,466,919 Sykes Apr. 12, 1949 2,499,100 Kessler Feb. 28, 1950 2,565,608 Hoff Aug. 28, 1951 

